Andy, remember that we began this discussion partly because of ‘jerky’ movements (& rubbing against certain surfaces seemingly in an effort to dislodge something); we concluded that there was likely some parasite (possibly introduced by nerite snails) that was causing a slew of bad symptoms.
If you look back at my first response in this thread, ( Post #2), I mentioned 4 possible reasons why the fish was behaving the way it was. Because there were so many possibilities, we needed to eliminate each possibility one at a time. If you recall ( or reread post #2), my thought was, considering your successes with the loaches breeding, the water was probably not the reason and the salt treatment would be a long shot but since you could not get the Paracleanse or AquaCura immediately, the salt treatment would be a good start since it would be immediate. If it worked , great, if it didn't work, it rules out the tank water as the problem. Well, just like in horse racing, long shots do come in sometimes. The fish is responding well with just that treatment. With that being the case, it ruled out the reason being a parasite. So from there, we then looked at WHY the salt would be working and found that his tank has Cyanobacteria in it. Cyano is a toxic bacteria when ingested. You said that the fish used to feed on the bottom (where the cyano is). One then can conclude that the
possibility exists that the fish consumed some Cyano and that cyano poisoning was in play. If the fish did consume some cyano, that effects the fish organs. A fish's organs MAY be able to regenerate but that is a slow process. Even my research on "how long does recovery from cyano ingestion take" said that "it can take weeks or even months." So there is no way I can tell you that in X amount of days or weeks or months the fish will be cured. And keep in mind that maybe he didn't eat the cyano directly but if his food had landed on it and it started to grow on the pellet(s), he may have ingested it that way.

There's just no way to know for sure without taking the fish to a Vet and having bloodwork and scans done to see what is going on since you don't have a 24/7/365 video of the fish tank. And that would cost a bazillion dollars. That's just unreasonable for a low cost fish. So the only way to prevent something like this from happening again is to not have cyano in the tank, ever!!!
Unfortunately, we can't ask our non English speaking pets what they did or how they feel so it becomes a case of trial and error. Just like when you go to your Doctor with a problem, the first thing the Dr does is ask questions. From your answers, the Dr formulates a plan and dispenses either medications or other therapies for recovery. I've asked you questions and made recommendations based on your answers. You have, on more than one occasion, made purchases based on the question, not the answer. I've said repeatedly, you have to have patience. Diagnostics is not an immediate result. Re having the AquaCura, it's not the worst thing to have on hand if you are getting new fish because there is always the
POSSIBILIITY that it can be needed in the future. In regards to the gram scale, if you had answered " No, I don't have a gram scale." I would have given you another method to apply the correct dosage
IF you had access to certain materials. YOU jumped and bought a gram scale based on the question. That's not having patience. Regarding the fish "rubbing against certain surfaces seemingly in an effort to dislodge something", you said there were fuzz spots on the fish. Are they still there in the same areas? If not, that is most likely what he was trying to rub off since he's not rubbing on anything anymore.
The ‘PrazMat’ combo is considered a ‘broad spectrum’ approach to the matter;
Sadly, some fish med companies make claims that their products don't always actually do. Fungus is a funny thing. It's a separate "animal " from bacteria so it needs different meds. If PrazMat doesn't include
fluconazole, it probably won't work on fungus
. Here's a catch tho, Columnaris, a common disease in fish that is often the cause of mouth "fungus" because it looks like a fungus, is not a fungus at all but a bacteria. So the manufacturer says on it's product that it will treat "mouth fungus" when in reality, it's treating a bacteria, not a fungus. People see mouth "Fungus" and think " Oh, this product treats fungus." when in fact it doesn't. Do you think the manufacturer is going to correct people and lose sales?
u had advocated the use of the stuff early on in our discussion—an obstacle to this was availability on my side of the border—u’d initially recommended the Fritz product—not available in Canada—but i found a substitute—the AquaCura formulation, which i think is the same as the Fritz product. SALT was a substitute for (or a precursor to) the PrazMat combo.
No, salt was another treatment method for something the PrazMat wouldn't treat. Reread the thread.
Here’s a link discussing what it does:
Review of Prazi-Met 10g Fish Treatment for Effective Parasite Control When it comes to maintaining the health of ytheir aquarium, ensuring that ytheir fish are free from parasites and diseases is paramount. Prazi-Met by Aquacura is a product that promises to deliver effective parasite control...
www.reviewaqua.com
So now i have the stuff in hand; i’m not ‘insistent’ on using it—honestly, i’d rather not—but i don’t know how much more the salt can do. Per your advice i’m willing to give the ‘salt cure’ more time, but, based on your experience, do u have a ballpark amt of time that might take? Or is this process a total crapshoot w/nothing quantifiable?
What i called ‘fungus’, under his mouth—i’m pretty sure it’s not his scales—BUT, oddly, it became more visible w/the camera—that’s when i noticed it—i was initially trying to capture certain positions he’d assume—that’s when i saw it (sorry the pic is crummy

).
Without good clear pictures and history, it's very difficult to make a concrete diagnoses. Even if it's fungus, that's the least of his problems.
I won’t try anything until i get the weighing device; in the meantime i’ll keep checking the ammonia status & changing the water.
(I never dismiss/ignore any of your advice!!!)
I believe I addressed the rest of your post in that first section. The salted water is something the fish can live in forever so not something to be concerned about being in for longer than just a treatment. When/if the fish recovers, it will be up to you then if you want to continue using it. If you stop it and the fish stops behaving "normally", you'll know your water lacks something the salt supplies for the fish and should continue using it.
For now, I would continue the salted water treatment and just keep trying to feed a bloodworm or pellet once per day or every other day. I would try just dropping the pellet or bloodworm into the tank and observe his reaction to it from a distance. If he shows no interest in it in the first 10-15 minutes, remove it from the tank so that it doesn't foul the water. That is all I would do other than changing the water every 2 -3 days. The rest is just up to the fish.